Manufacture of tar acids.



I. & S. McDOUG-ALL & F. HOWLBS. MANUFACTURE 01" TAB. ACIDS.

APPLICATION FILED JUNE 6, 1913.

Patented Nov. 4, 1913.

yaZZ 152d j 7% Fred, flow/Zea,

eyJTJo W. I. Mien/u covery of the caustic soda.

UNITED STATES PATENT onion RfiAC MQIDOUGALL, SIDNEY McDOUGALL, AND FRED HOWLES, OF MANCHESTER, ENGLAND.

MANUFACTURE 0T TAR ACIDS.

$peci flcation of Letters Patent.

Application filed June 6, 15913.

Patented Nov. 4, 1913. Serial No. 772,211.

To all whom 2'25 may concern Be it known that we, ISAAC MoDoUoALL, SIDNEY McDoUoALL, and FRED HDWLES, subjects of the King of Great Britain and liela nd, all residing at 66 and 68 Port street, Manchester, England, have invented certain new and useful Improvements in the Manufacture of Tar Acids, of which the following is a specification.

Thls invention relates to the manufacture or recovery of tar acids such as phenol, cresol and their higher homologues, and has for its object to provide an improved process for obtaining the said acids from tar distillates, which is very etficient and economical to carry out. Heretofore various processes have been proposed for obtaining the said acids, the method at present employed consisting in the utilization of caustic soda for separating the acids from the hydrocarbon oils in the tar distillate and the subsequent separation by chemical means of the acids from the caustic soda solution. Such process is expensive to carry out as it involves the employment of a complicated plant and also the chemical separation and subsequent re- There is also a considerable loss of the latter material during the carrying out of the process.

It is impossible to recover the tar acids alone by extraction by the use of the ordinary organic solvents for the latter dissolve not only the tar acids but also the hydrocarbon oils and produce a homogeneous mass.

By investigation and experiment We have found that the tar acids can be extracted from the tar distillate, comparatively free from hydrocarbon oils, by the utilization as the extracting agent, of alcohol mixed with a suitable proportion of water. We find that good results are obtainable, when treating a high boiling point distillate, with from .23 to 25 per cent. of water added to commercial a cohol (2'. e.purified methylated spirits), and when treating a low boiling point distillate such as carbolicoil, with up to 40 per cent. of Water added to commercial alcohol, but we do not limit ourselves to the employment of such specific proportions as the latter may be varied to suit the' nature of the product being treated. Excess of water prevents the separation of some of the tar acids while deficiency of water causes some of the oils to dissolve along with the acids. We may add two gallons of the can be drawn off from the receptacle or YES-7 sel in which the extraction has been accomplished, the alcohol being then recovered in the usual manner.

The extraction of, for example, blast furnace creosote oil, may be carried out as follows: Agitate one liter of creosote at ordi nary atmospheric temperature with one liter of alcohol containing 27 per cent. of water: allow to settle; separate the partially spent creosote from the acid extract; agitate the partiafily spent creosote with a further quantlty o 27 per cent. of water: ailow to settle and separate: the remaining partially spent creosote may be again agitated with a further onehalf liter of alcohol containing 27 per cent. of water. The last or third treatment prac tically completes the extraction of the phe noloi-ds. Each extraction and separation occupies about one hour. The extracts from each treatment are put together and distilled to recover the alcohol. The residue consist- .ing of crude acids and water is allowed to stand until separation is complete. The water which separates is added to the distilled alcohol. The acids are purified in the usual way by distillation. A small quantity of Water first distills over and this is also added to the recovered alcohol. The distilled acids from this treatment measure 220, c. cs. The residual oil which contains about 15 per cent. of alcohol is heated until the alcohol is all distilled over when the residue measures 768 0. cs. The distillation is a simple process owing to the boiling points of alcohol and oil being so far apart. The reone-half liter of alcohol containing mainder of the original liter of creosote consists of pitch. With ordinary care the total loss of alcohol is under per cent.

The accompanying diagram illustrates a plant suitable for use in carrying out our aforesaid process. i

The vessel a, contains alcohol mixed with the desired roportion of water having regard to the istillate to be treated. The latter is contained within the vessel a having an agitator c of any convenient form arranged therein. The alcohol and water mixture is fed into the vessel 1) and is agitated along with the distillate. The tar acids separated from the distillate by the alcohol and water are led off into the vessel 03 while the hydrocarbon oils are passed intov the vessel e. From the latter, the said oils are preferably returned two or more times to the vessel 12 by the pump represented by f so as to insure a high degree of efliciency in the extraction of the tar acids. A test cock is provided represented by g, to test the delivery from the vessel 6 so as to ascertain if tar acids or oils are passing therefrom. The flow to the vessels dor e is controlled accordingly.

The alcoholic extract (or tar acids, alcohol and water) is delivered by the pump 2' to the still it heated in a suitable manner, the alcoholic vapors given ofi' passing through a condenser j on their'way to the alcohol store k. The tar acids and water then pass to a separating vessel m where owing to their different specific gravities, the tar acids can be separately drawn oil by the pump a and delivered to the acid still 0 and finally through the condenser 32 to the acid store g. After the acids, which are heavier than the water, have been drawn ed, the water is by way of the conduit r to the alcohol store is to provide a mixture of the strength originally determined. The hydrocarbon oils, after extraction is completed, are delivered by the vessel e to the oil still a suitably heated to vaporize any alcohol contained therein, the alcohol passing to the condenser j and store is. The oil is subsequently delivered "from the still by means of a pump t to a store tank-(not shown). Suitable control valves are provided for directing and regulating the flow of liquid between the various vessels: also pi es u for allowing of the free circulation ot vapor between the vessels a, b, d and e as the said vessels are filled and emptied.

It will be understood that we do not limit ourselves to the form of plant described and illustrated but may modify the same to suit requirements. The illustration merely shows one arrangement of plant suitable for use in carrying out our process.

Having now described our invention what we claim as new and desire to secure by Letters Patent is 1. Process for the manufacture or recovery of tar acids from tar distillates, consisting in treating the latter with a mixture of alcohol and water, as set forth.

2. Process for the manufacture or recovery of tar acids from tar distillates consisting in agitating the latter with a mixture of alcohol and water, allowing the liquid to settle, and separating the partially spent distillate from the acid extract, the said process beingrepeated at least once, the extracted acid being subsequently distilled, as set forth. drawn ofi' by the same pump a and passed I In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

ISAAC MODOUGALL. SIDNEY. MODOUGALL. FRED HOWLE S.

Witnesses:

ARTHUR HUoHEs, Rosana Tamas. 

